Abstract:

A broad-perspective analysis of the ground-water resources and present
and possible future water development and management in the Souris-Red-Rainy Region is presented. The region includes the basins of the Souris River within Montana and North Dakota; the Red River of the North in South Dakota, North Dakota, and Minnesota; and the Rainy River within Minnesota. The region includes 59,645 square miles, mostly in North Dakota and Minnesota. The terrain is relatively flat, but ranges in altitude from 2,541 to 750 feet. Annual average precipitation ranges from 14 inches in the west to 28 inches in the east and about 75 percent of it is rain. The mean annual snowfall ranges from 32 inches in the west to 64 inches in the east. Temperatures range from -55° to 118° F (-48.3° to 47.8° C). Irrigation is needed at least part of the time to assure crop production, particularly in the western part of the region.
Sand and gravel deposits in the drift form the most important freshwater
aquifers. Other aquifers are found in at least parts of the region in the
Precambrian, Paleozoic, Cretaceous, and Tertiary rocks. The potentiometric
surface in the bedrock aquifers generally decreases in altitude toward the Red River of the North, indicating that the general direction of ground-water movement is toward the river. Ground water with less than 3,000 milligrams per liter dissolved solids is available throughout the region. Ground water with less than I ,000 milligrams per liter occurs in most of the region east of the Red River of the North and in most of the shallow aquifers west ofthe river. The total volume
of water available from storage having less than 3,000 milligrams per liter
dissolved solids is estimated to be 5x I ()8 acre-feet. In addition to the fresh
and slightly saline water, the region has abundant highly mineralized water
that can be considered as a resource. Yields of wells in individual bedrock
aquifers are generally less than I 00 gallons per minute but locally yields may
be as much as 500 gallons per minute and more. Yields in drift aquifers are
frequently less than I 00 gallons per minute but range from 5 to I ,000 gallons
per minute. In a few places outwash yields more than 1,000 gallons per
minute.
Ground water is the sole or a primary source of water supply in much of
the region, including supplies for irrigation, domestic and livestock,
municipal, and industrial needs. Reportedly, the potential irrigation
development is l ,550,000 acres, as compared with 50,200 acres in 1975. Both
ground- and surface-water supplies would be required to meet these
demands. Rural domestic and livestock water supplies are derived almost
entirely from ground-water sources. Smaller communities and towns
generally rely on ground water, and the cities and industries use ground
water, surface water, or both. The municipalities using surface water
generally depend upon reservoir storage. Water quality rather than quantity
is the greater water-supply problem for many communities in the region.
Increased demands on both ground-water and surface-water supplies
likely will be made in the future. Storage of surface water in the
ground-water reservoirs during times of surplus for withdrawal during
times of scarcity would aid in meeting these demands. The surplus (flood)
water is of better chemical quality than underlying ground water in parts of
the western half of the region. Freshwater could be stored in saline- or
freshwater aquifers, and pumped out later, as needed. Thus, the
ground-water reservoirs have a definite present and potential role in water
management.
To understand the hydrologic system for management purposes there is a
need to determine more adequately the geologic and hydrologic
characteristics of existing aquifers and the location of new aquifers. Also, as
pumping and other stresses on any part of the hydrologic system affect other
parts of the system, monitoring programs ideally should be started and
maintained to detect changes and determine effects of the stresses.
Many alternatives are available for managing water in the region. Some
of these are operational and others are undergoing research. Adequate
hydrologic information is needed to aid in solving problems of water
supply, use, and pollution.